bug#81514: 32.0.50; Eglot messages progress reporter shows errors

> From: "Jacek Świerk" <[email protected]>
> Date: Wed, 29 Jul 2026 09:41:39 +0200
> 
> When Eglot is configured with `eglot-report-progress` set to `messages`, it
> reports an error while trying to use the progress reporter in a nontrivial
> project.
> 
> Reproduction using rust-analyzer:
> 1. Clone https://github.com/BurntSushi/ripgrep
> 2. Open ripgrep/crates/core/main.rs
> 3. M-: (setopt eglot-report-progress 'messages)
> 4. M-x toggle-debug-on-error
> 5. M-x eglot
> 
> Debugger entered--Lisp error: (wrong-type-argument sequencep 100)
>    progress-reporter-echo-area((7 . [1785304002.532535 nil nil "[eglot] 
> ripgrep rustAnalyzer/Building compile-time-deps: Building 
> compile-time-deps..." 1 0.2 nil nil]) 7 100)
>    progress-reporter-do-update((7 . [1785304002.532535 nil nil "[eglot] 
> ripgrep rustAnalyzer/Building compile-time-deps: Building 
> compile-time-deps..." 1 0.2 nil nil]) 100 nil)
>    eglot--reporter-update((7 . [1785304002.532535 nil nil "[eglot] 
> ripgrep rustAnalyzer/Building compile-time-deps: Building 
> compile-time-deps..." 1 0.2 nil nil]) 100 nil)
>    #f(compiled-function (arg1 arg2 arg3 arg4 &rest rest) #<bytecode 
> 0x1c7b74ccff3232d6>)(#<eglot-lsp-server 1008c31da7cc> 
> "rustAnalyzer/Building compile-time-deps" 100 nil)
>    #f(compiled-function (arg1 arg2 &rest rest) "Handle $/progress 
> notification identified by TOKEN from SERVER." #<bytecode 
> -0x35b89fe1a323862>)(#<eglot-lsp-server 1008c31da7cc> $/progress :token 
> "rustAnalyzer/Building compile-time-deps" :value (:kind "end"))
>    apply(#f(compiled-function (arg1 arg2 &rest rest) "Handle $/progress 
> notification identified by TOKEN from SERVER." #<bytecode 
> -0x35b89fe1a323862>) #<eglot-lsp-server 1008c31da7cc> $/progress (:token 
> "rustAnalyzer/Building compile-time-deps" :value (:kind "end")))
>    eglot-handle-notification(#<eglot-lsp-server 1008c31da7cc> $/progress 
> :token "rustAnalyzer/Building compile-time-deps" :value (:kind "end"))
>    apply(eglot-handle-notification #<eglot-lsp-server 1008c31da7cc> 
> $/progress (:token "rustAnalyzer/Building compile-time-deps" :value 
> (:kind "end")))
>    #f(compiled-function (server method params) #<bytecode 
> 0x1f1068c682e838aa>)(#<eglot-lsp-server 1008c31da7cc> $/progress (:token 
> "rustAnalyzer/Building compile-time-deps" :value (:kind "end")))
>    jsonrpc-connection-receive(#<eglot-lsp-server 1008c31da7cc> (:jsonrpc 
> "2.0" :method "$/progress" :params (:token "rustAnalyzer/Building 
> compile-time-deps" :value (:kind "end"))))
>    #f(compiled-function (conn msg) #<bytecode 
> 0x1bafe9b6d4ce09dc>)(#<eglot-lsp-server 1008c31da7cc> (:jsonrpc "2.0" 
> :method "$/progress" :params (:token "rustAnalyzer/Building 
> compile-time-deps" :value (:kind "end"))))
>    apply(#f(compiled-function (conn msg) #<bytecode 0x1bafe9b6d4ce09dc>) 
> (#<eglot-lsp-server 1008c31da7cc> (:jsonrpc "2.0" :method "$/progress" 
> :params (:token "rustAnalyzer/Building compile-time-deps" :value (:kind 
> "end")))))
>    timer-event-handler([t 27241 37827 781121 nil #f(compiled-function 
> (conn msg) #<bytecode 0x1bafe9b6d4ce09dc>) (#<eglot-lsp-server 
> 1008c31da7cc> (:jsonrpc "2.0" :method "$/progress" :params (:token 
> "rustAnalyzer/Building compile-time-deps" :value (:kind "end")))) nil 
> 734000 nil])
> 
> This seems to be introduced by the following commit
> https://github.com/emacs-mirror/emacs/commit/b6849229003f214570acedfa7e2755051c0e4305
> and most likely affects Emacs 31 as well.

Thanks.

Stéphane, please look into fixing this.